High voltage in-line disconnect switch

ABSTRACT

A switch is provided for insertion directly into a high voltage power line to provide means for electrically disconnecting an extension of the line. The switch employs an insulator having high tensile strength and a high dielectric constant which can physically support a power line and also withstand the electrical forces applied through the line. The electrical circuits are either completed or broken through action of a switch blade which can conduct electric current between hardware components connected to end fittings on the insulator. The end fittings are tapered and faced by steps to prevent their being pulled from the hardware or rotated with respect to the hardware.

United States Patent Anderson [451 May 28, 1974 HIGH VOLTAGE lN-LINE DISCONNECT SWITCH lnventor: Ronald Vernon Anderson, St.

Charles, Mo.

International Telephone and Telegraph Corporation, New York, N.Y.

Assignee:

Filed: Jan. 30, 1973 Appl. No.: 327,987

U.S. Cl. 200/48 R, 174/179 Int. Cl. H0lh 31/00 Field of Search 200/48 R, 48 KB; 174/176,

References Cited UNITED STATES PATENTS Lankford 200/48 R Hulteen et al. 200/48 R 3,621,160 ll/l97l Turner ..200/48R Primary ExaminerHerman Hohauser Attorney, Agent, or FirmJ. B. Raden; Delbert P.

Werner ABSTRACT A switch is provided for insertion directly into a high voltage power line to provide means for electrically disconnecting an extension of the line. The switch employs an insulator having high tensile strength and a high dielectric constant which can physically support a power line and also withstand the electrical forces applied through the line. The electrical circuits are either completed, or broken through action of a switch blade which can conduct electric current betweenhardware components connected to end fittings on the insulator. The end fittings are tapered and faced by steps to prevent their being pulled from the hardware or rotated with respect to the hardware.

6 Claims, 10 Drawing Figures PATENTEDIAY 28 I974 SHEEI 1 BF 4 FIG. .3

FIG. 2

HIGH VOLTAGE IN-LINE DISCONNECT SWITCH BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to switch assemblies for use in electric primary power distribution circuits. It relates particularly to in-line disconnect switches which are to be placed directly in mechanical as well as electrical series with the power lines in such a way that they also provide part of the mechanical structure of the lines. The switches carry the full current in the lines when they are closed; and provide effective electric open circuits in the lines when they are open, to enable electrical isolation of branches of a power network. The switch assemblies maintain structural links in the lines at a level strong enough to physically support the lines. The present invention relates further to means for maintaining positive angular alignment between the ends of the switch assemblies and to the maintenance of alignment of the electrical contact elements of the switch.

2. Description of the Prior Art The prior art in-line disconnect switches for electrical power distribution systems include arrangements of insulators which are terminated by end fittings. The end fittings are secured to the insulators by cement which is intended to secure the end'fittings from coming loose or rotating relative to the insulators and to each other. Characteristically, the end fittings have been cylindrical in form. The mounting hardware for the electric switch has been fastened to the end fittings by means of U bolts or combinations of brackets and bolts. A patent exemplary of this prior art is US. Pat. No. 3,499,129 entitled Line Tension High Voltage Current Interrupter, issued in the names of L. A. Halteen and W. H. Gilliland on Mar. 3, 1970.

It has been difficult with the prior art to maintain positive angular orientation between the mounting surfaces of the insulator end fittings and mating surfaces of the mounting hardware. Frequently, it has been necessary to readjust the switches in the field when they have slipped out of alignment. In addition, where the end fittings are cylindrical there is no positive means for preventing the insulator and end fitting assembly from sliding out of the U-bolt or other fastener along the longitudinal axis of the assembly or angularly about the axis.

SUMMARY OF THE INVENTION Objects of the invention include the provision in an in-line disconnect switch of means to maintain angular orientation between an insulator, metallic insulator end fittings and mating surfaces of electric switch-blade mounting hardware. The objects include preventing the metallic insulator end fittings from sliding relative to the insulator either about or along the longitudinal axis of the insulator. Objects include preventing motion between the end fittings and mounting hardware. Other objects include holding the blades of the electric switch in alignment with each other.

To attain the objectives referred to above, a number of features have been incorporated in in-line switches according to the present invention. These include crimping metallic end fittings onto the ends of insulator rods to securely attach these parts together. Flat steps are provided on the insulator metallic end fittings with are engaged with flat surfaces on the switch castings,

thereby preventing rotation of the switch casting relative to the metallic end fittings. The metallic end fittings are tapered and fitted to the switch castings so that tension applied from the insulator will not pull the end fittings from the castings. These measures insure positive orientation and alignment between the insulator, the end fittings, the mounting hardware, and the switching elements at all times after the switch has been assembled.

BRIEF DESCRIPTION OF THE DRAWINGS The above mentioned and other features and objects of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a plan view in partial section of an in-line disconnect switch according to the invention,

FIG. 2 is a bottom view of the embodiment of FIG.

FIG. 3 is a sectional view of a spacer of use in an inline switch,

FIG. 4 is a view in partial section of a metallic end fitting used to support and secure insulators,

FIG. 5 is a side view of FIG. 4,

FIG. 6 is a bottom view of FIG. 5,

FIG. 7 is a plan view of a switch casting depicting hinge elements of use in the practice of the invention,

FIG. 8 is a bottom view of the casting shown in FIG.

FIG. 9 is a side view of the casting shown in FIG. 7, and

FIG. 10 is a side view of the casting shown in FIG. 9.

DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Turning now to FIG. 1, there is disclosed a plan view of a completely assembled in-line disconnect switch according to the invention. In this view, the digit 2 refers to a ribbed porcelain insulator through which a fibre glass rod insulator 4 is extended into metallic end fittings at 6 and 8. A slurry of urethane is'used as a sealant between the fibre glass rod 4 and the inner wall of the insulator 2. The end fittings 6 and 8 are crimp-fitted to the fibre glass rod to secure a strong fit.

The metallic end fittings 6 and 8 incorporate flat steps which are secured against flat mating surfaces on the switch casting or switch support bodies, 12. The metallic switch blade 14 has in fact a double blade (indicated in FIG. 2 as 14 and 14) which is hinged to the switch casting, or hinge casting, 12 about a pivot point 16. A pull ring at 18 is latched by element 19 to the switch casting l0 and is designed to enable safe disconnect, through use of a proper tool, of the switch blade 14 from contacts afiixed to the switch casting 10. A spring element at 20 is provided to engage the blade 14 to hold it open in a position from its position when closed and to reduce the chances of accidental contact by linemen.

The switch castings 10 and 12 and the metallic end fittings 6 and 8 are secured together by a pair of U bolts 22 and 24, the ends of which are shown enclosed in FIG. 1 by respective nuts 26, 28, 30 and 32.

A bottom view of the assembly of FIG. 1 is shown in FIG. 2, where the same numbers are used to designate 3 like parts. In this view, a further showing is provided of the manner in which the end fittings 6 and 8 are fastened to the switch-castings l and 12' by U-bolts 22 and 24. In addition, a hinge element 32 is indicated to show means enabling'the switch blades 14 and I4 to rotate about the pivot point 16, of FIG. I. a

FIG. 3 is a sectional view. on an'enlarged scale showthis view. The opening enclosed byithe wall 44-is'p'rovided to receive one end of a rod of fibre glass 4 (FIG. I) or a rod of other suitable insulating material of relatively high structural strength. Details of construction include the intersection54 between a wall 50 and a wall 52, as well as an intersection between wall 44" and wall 50. A slurry of urethane, or other sealant, may be used to help seal any space between the wall 44 and an insulator rod. The metallic end fitting 6, in a preferred embodiment, is crimped around the fibre glass rod to insure a positive fit between the two elements and to prevent either lateral or rotary motion between the two. 1

The end fitting 6 includes a flat stop at 46 which is provided to enable'positive contact to be. established with the correspondingswitch casting 12. The hole at 48 in the flat extension link 6 is provided to enable direct mechanical and electrical connections to be completed. with a powerline.

The end fitting 6 (as well as the end fitting 8) .is a section of a cone, havingthe large end, or base of the cone situated at the top adjacent the flat extension link 6 in the view shown'in FIG. 4. The resulting taper makes it possible to more effectively restrict motion parallel to the center line of the end fittings by use of clamps, such as 22 and 24 in FIG. I. It will be seen from FIG. 1 that tensile forces applied to the fibre glass rod 4 and to the metallic end fittings6'and 8' will be prevented from pulling 6 and 8 out of the clamps 22 and 24 by virtue of the force applied by the clamps and the taper on 6 and 8. 1

' FIG. 5 is a side view of the metallic end fitting6 showing a difierent orientation of the extension link 6' and the flat step 46. Fitting 6 is again shown to taper outward from the bottom.-

FIG. 6 is a bottom view of FIG. 5. FIG. 6 indicates the positions of various parts of the opening in 6, depicting a wall at 44, and a junction at 54 between the flat end 52 of the opening and the wall 50. The extent of the conical taper of the end fitting 6 is indicated by th concentric rings 56 and 58.

FIG. 7 is a plan view of a switch casting oriented in the position of casting 12 (which may also be referred to as a hinge casting as distinct from in FIG.- 1, and depicting hinge elements 32. It is apparent from inspection of FIGS. 1 and 9 that the various openings shown in FIG. 7 correspondto the positions of fastener elements in FIG. 1.

FIG. 8 is a bottom view in partial section of FlG..7 showing further details of construction of the. hinge element 32 and of other parts of the hinge casting I2.

FIG. 9 is a side view of the switch casting of FlG. 7-

depicting further relationships of the hinge element 32 as well as other features. Of particular interest is the flat area 46 which is provided to mate with the flat step 46shown in FIGS. 4 and 5to enable positive contact to be established between the metallic end fitting 8 and the switch, or hinge, casting l2.

' FIG. 10 is a view-showing the right side of the switch casting as depicted infFlG. 9. In this view, the hinge ele ment 32 is shown fromjanother view. The relationship of the flatarea 46' to the casting I2 is shown in a new perspective. I j

While the principles of the invention-have been described above in connection with specific apparatus and applicationsfit is to'be understood that this descriptionismade" only by way of example and not as a limitationon the scope'of the invention.

lclairnr II l.An in-line disconnect switch, comprising insulation means including a rod formed from insulatingmaterial of' high tensile strength, means securing a metallic end fitting to each end of the rod to enable a mechanical connection to be completed between two ends of a power line, said means securing said metallic end fittings and rod I together serving to prevent rotation of saidend fittings relative to each other about a longitudinal axis through the rod,

an electric switch comprising switch support bodies interconnectable for electrical conductivity through mechanicallinkages including a metallic switch blade, and

means for mating together said switch supportbodies and said metallic endfittings to prevent translational and rotary motion between them,

said means for matingii'ncluding mating elements on at least one of said switch support bodies and on one of said metallic end fittings, andv i clamping means for holding-together a mating element on at least one end fitting and a mating element on at least one switch support body to prevent rotary motion between the electric switch and the metallic end fittings.

2. A switch as claimed'in claim I, in which I I the rod formed of insulating material is of fibre glass,

and i I themetallic end fittings are crimped to the rod.

3. A switch as claimed in claim 1, in which the rod fonned of insulating material is of fibre glass,

a chemical sealant is applied between the fibre glass rod and the metallic end fittings, and

the metallic end fittings are crimped to the rod.

4. A switch as claimed in claim 1, in which each metallic end fitting is shaped externally substantially as a section of a cone," I

each metallic end'fitting fits over one end of the rod so that its small end is located adjacent to the rod,

and I t I 7 said clamping means in cooperation with the taper of said cone prevents translational motion resulting from forces tending to pull the end fittings towards the rod. I

5. A switch as claimed in claim 1, in which the means for mating includes a flat 'portion on at least one end fitting and a matching flat portion on a corresponding switch body.

6. A switch as claimed in claim I, in which each metallic end fitting is shaped externally substantially as'a section of a cone,

6 each metallic end fitting fits over one end of the rod from forces tending to pull the end fittings towards so that its small end is located adjacent to the rod, h d d said clamping means in cooperation with the flat pormetallic end fitting and a matching flat portion on 5 l of each fimng and the matching flat p.or each Switch Casting tron of each swltch body prevents rotary motion said clamping means in cooperation with the taper of betwfiefl the end gs and the Switch e said cone prevents translational motion resulting said means for mating includes a flat portion on each 

1. An in-line disconNect switch, comprising insulation means including a rod formed from insulating material of high tensile strength, means securing a metallic end fitting to each end of the rod to enable a mechanical connection to be completed between two ends of a power line, said means securing said metallic end fittings and rod together serving to prevent rotation of said end fittings relative to each other about a longitudinal axis through the rod, an electric switch comprising switch support bodies interconnectable for electrical conductivity through mechanical linkages including a metallic switch blade, and means for mating together said switch support bodies and said metallic end fittings to prevent translational and rotary motion between them, said means for mating including mating elements on at least one of said switch support bodies and on one of said metallic end fittings, and clamping means for holding together a mating element on at least one end fitting and a mating element on at least one switch support body to prevent rotary motion between the electric switch and the metallic end fittings.
 2. A switch as claimed in claim 1, in which the rod formed of insulating material is of fibre glass, and the metallic end fittings are crimped to the rod.
 3. A switch as claimed in claim 1, in which the rod formed of insulating material is of fibre glass, a chemical sealant is applied between the fibre glass rod and the metallic end fittings, and the metallic end fittings are crimped to the rod.
 4. A switch as claimed in claim 1, in which each metallic end fitting is shaped externally substantially as a section of a cone, each metallic end fitting fits over one end of the rod so that its small end is located adjacent to the rod, and said clamping means in cooperation with the taper of said cone prevents translational motion resulting from forces tending to pull the end fittings towards the rod.
 5. A switch as claimed in claim 1, in which the means for mating includes a flat portion on at least one end fitting and a matching flat portion on a corresponding switch body.
 6. A switch as claimed in claim 1, in which each metallic end fitting is shaped externally substantially as a section of a cone, each metallic end fitting fits over one end of the rod so that its small end is located adjacent to the rod, said means for mating includes a flat portion on each metallic end fitting and a matching flat portion on each switch casting, said clamping means in cooperation with the taper of said cone prevents translational motion resulting from forces tending to pull the end fittings towards the rod, and said clamping means in cooperation with the flat portion of each end fitting and the matching flat portion of each switch body prevents rotary motion between the end fittings and the switch bodies. 